1. Field of the Invention
The present invention relates to an image processing apparatus, image processing apparatus control method, ophthalmologic apparatus, ophthalmologic apparatus control method, ophthalmologic system, and storage medium.
2. Description of the Related Art
A tomographic imaging apparatus for the eye portion of an eye to be examined, such as an optical coherence tomography (OCT), allows three-dimensionally observing the internal state of a retina layer. The tomographic imaging apparatus has recently received attention because it is useful for more accurately diagnosing a disease. As one form of the OCT, there is known a TD-OCT (Time Domain OCT) which is a combination of a wideband light source and a Michelson interferometer. The TD-OCT is configured to measure interference light with backscattered light from the signal arm by scanning a delay of the reference arm, and obtain depth resolution information. However, high-speed image obtainment is difficult for the TD-OCT. To more quickly obtain an image, an SD-OCT (Spectral Domain OCT) is known as an OCT which uses a wideband light source and obtains an interferogram by a spectrometer. There is also known an SS-OCT (Swept Source OCT) which uses a high-speed wavelength-swept light source as the light source and measures a spectral interference by a single-channel photodetector.
If a morphologic change of the retina can be measured in tomographic images captured by these OCTs, the stage of a disease such as glaucoma, and the degree of recovery after treatment can be quantitatively diagnosed. Conventionally, imaging by the OCT is performed in an apparatus-specific coordinate system. However, for an eye portion, it is desirable to obtain an image considering the course of nerve fibers. FIG. 9 is a schematic view showing the course of nerve fibers. In FIG. 9, each thin curve N represents a nerve fiber, M near the center represents a macular region, an ellipse D represents an optic papilla, and each thick curve V represents a blood vessel.
Japanese Patent Laid-Open No. 2010-125291 discloses a technique of creating a tomographic image along the course of nerve fibers. In Japanese Patent Laid-Open No. 2010-125291, a section along the course of nerve fibers, which is designated by an operator from three-dimensional OCT data captured in an apparatus-specific coordinate system, is created as a tomographic image. Further, imaging is performed along the course of a nerve fiber layer.
To diagnose a disease, sides above and below a nerve fiber to be diagnosed, and its nose and ear sides are desirably captured in one section. However, the technique in Japanese Patent Laid-Open No. 2010-125291 does not guarantee imaging of tomographic images perpendicular and parallel to the course of nerve fibers. For example, the pores of the lamina cribrosa become large in the vertical direction, so a change of the shape readily appears in the vertical direction. Unless imaging is executed in accordance with the coordinate system of the eye portion of each individual, it is hard to obtain an image effective for diagnosis and analysis.